I'm looking to buy my first torque wrench to use when working on my 240D. I need recommendations on what to look for and what this work will require.

There is a large bolt on the front of the crank that tightens the damper there. It requires 200 lbs torque. I have had to rent a torque wrench with that scale to get that one set. Sort of depends on whether you are planning on replacing the front seal or not, but that is a consideration. $ort of pricey for the big torque wrenches though.
Other than that, there are other good tool pros here that will steer you right.

I torque wrench is the one tool where you always want to put quality and accuracy ahead of price.

If you can find one, an old Proto click adjust. They're a Richmond/Sternavent(sp?) design and "were" the best out there.

Mac tools also makes a good click wrench in the 50-250 range if you need that high.

The most accurate torque wrench on the market happens to be the cheapest one it is the type with the scale running horizontally across the top with a pointer a plastic handle that you must keep straight with the main bar that runs vertically and the little pointer points at the scale which is marked from 0 in the center increasing in foot pounds as the pointer moves to the outer edge see attached picture not only is it cheap but it is more accurate than a $500 snap on click wrench or any other bar none let the argument begin but be prepared I can back up my claims with well proven scientific facts And even my Saturn owners manual says so. But the aircraft industry has spent a ton of money on this and the simple cheap one wins by a mile.
Dave S

That may be the most accurate type.... and that is the only type I have.. both ft/lbs and in/lbs....
But it is not easy to use correctly in tight spaces...
I wish I had a ' pretty good' click type myself...

I just assumed click-type as that is what more people use now days. You are correct in that a manual torque wrench is very accurate, but you still have differences between the cheap and expensive ones. The aircraft industry (at least the bigger manufacturers) use different kinds and usually have torque testing machines on hand to regularly test their torque wrenches. Us mechanics just usually send them off once a year to get re-calibrated.

This is the kind of information that I needed and thats why the ? I assumed the more expensive models were better and didn't know that others would need to checked for accuracy.

Another consideration is that the "click' type of wrenches usually ratchet. The "beam" type do not.

A bolt is really a spring and when you torque a bolt what you are really doing is adjusting how much you are stretching the spring to preload it.

People tend to approach this with awe, magic and BS. It is not rocket science. Almost any decent torque wrench is adequate for your use.

I would buy a cheap 1/2" drive torque wrench and shop for a little better 3/8" drive that measures inch/lbs.

Now for the flame bait: As a teenager working in a motorcycle shop I was taught how to torque bolts by feel without a torque wrench. It can be done, I have checked myself with a torque wrench and I am pretty accurate. I use a torque wrench on critical parts anyway.

I don’t know about jet liners the biggest plane I ever worked on was a Lear jet got to fly it for a minute too what a blast. But in a general aviation shop be it light planes or helicopters you would be reprimanded or even fired for using a click type torque wrench. And I know since at least 1996 major automakers have been moving away from the click type wrench Saturn strongly advises against there use. The click type torque wrench is wildly inaccurate and does not even really measure torque as in clamping pressure but is much more likely to measure friction between fasteners. Why are we evan talking about somthing as outdated as tourque wrenchs when we should be using degrees of rotation
Dave S

.... Why are we evan talking about somthing as outdated as tourque wrenchs when we should be using degrees of rotation
Dave S

One reason is because all the shop manuals specify torque settings, and mention nothing about degrees of rotation. The MB shop books all show the "manual" type torque wrenches, just for what it's worth.

There is a lot to be said for developing the "feel" for how tight is enough. I try to use 3/8 drive for just about everything except the really big stuff, it's usually harder to overtighten with a smaller handle.

Kevin

I don’t know about jet liners the biggest plane I ever worked on was a Lear jet got to fly it for a minute too what a blast. But in a general aviation shop be it light planes or helicopters you would be reprimanded or even fired for using a click type torque wrench.


Well, I know a bit about overhaul and maintenance of jet engines and every single overhaul shop of large turbofan engines uses the click type torque wrench. They are calibrated on a yearly basis and the accuracy of these wrenches is about 1 ft.-lb. or so. The accuracy of the traditional bar wrench may be better than the click type, however, the traditional wrench is fraught with the risk of operator error. It is virtually impossible to for the average mechanic to operate the traditional wrench to an accuracy of 1 ft.-lb.

I use a Snap On and I recommed it if you want to spend the money. They last forever and Snap On will check it any time you want. I just had it done back in March.

“One reason is because all the shop manuals specify torque settings, and mention nothing about degrees of rotation. The MB shop books all show the "manual" type torque wrenches, just for what it's worth.”
I don’t know what manual you are reading but my hard copy MBZ manuals all specify angle of rotation for critical joints such as head bolts bearings ect
The FAA specifically recommends against the use of click type wrenches for aircraft use I can look it upand quote chapter and verce. They do prefer the use of the new model TES or equivalent such as the snap on direct reading torqometer wrench it can be held at any angle without affecting accuracy because of this and other factors they are preferred over beam type torque wrenches. I don’t know about big jet engines but on small planes torque means just about didily squat for critical joints. Who cars if your bolt is torqued on at 800 ft lbs if your clamping pressure is 0 lbs it will simply fly apart no matter how much torque is on the bolt if it has no clamping pressure which is what degrees of rotation and stretch to fit bolts assures you.
Dave S

The FAA specifically recommends against the use of click type wrenches for aircraft use I can look it upand quote chapter and verce.
Please do. Thanks.

" The click type torque wrench is wildly inaccurate and does not even really measure torque as in clamping pressure but is much more likely to measure friction between fasteners. Why are we evan talking about somthing as outdated as tourque wrenchs when we should be using degrees of rotation"---
Dave S

Dave, It is a good thing we are talking about it because you have COMPLETELY MISSED THE CONCEPT... as shown by your statements above..

NOTHING MEASURES THE CLAMPING FORCE..... and I have said this many times...and even in the last few days..... that the measurement of hold down force is only a wild extrapolation of what the engineers hope will be the corelation of the friction of the fasterner and the hole.....and THAT IS WHY IT IS IMPORTANT TO RUN A TAP INTO BOLT HOLES AND MAKE SURE THREADS ARE CLEAN AND 'LIGHTLY LUBED'.......

If you will REREAD your MB manual.... that reference to DEGREES OF ROTATION .... is only AFTER applying a specified amount of measured torque to the bolt.... let it rest.... then you use the 90 degree procedure ....

The click type torque wrench is wildly inaccurate and does not even really measure torque as in clamping pressure but is much more likely to measure friction between fasteners.

When used to torque a bolt with threads that are not frictionlesss, all torque wrenches, click type, or the traditional bar type, will result in reduced clamping pressure.

The whole process of torquing fasteners depends on very clean, friction free threads as Greg has explained. You cannot blame the click style torque wrench for a bad thread.

Dave and Greg, i think you are both largely correct about this. Truth is, we engineers have been trained to expect that joining by threaded fasteners is FOR MOST APPLICATIONS, highly variable and conservative use thereof dominates. However, in more critical and high performance applications such as head bolts, degree of rotation will provide a much more accurate measurement of joint preload. Studies have been done, such as J.C. Blake and H.J. Kurtz "The Uncertainties of measuring Fastener Preload"(Machine Design, vol 37, 9/30/65, pp. 128-131) under rather precise conditions. On a sample of 20 unlubricated and then lubricated 1/2-20 Bolts, torqued to 800 in-lb, mean values of about 7700 lb were nearly identical. However, the standard deviations for the samples were 1100 and 680 lb respectively! My conclusion - torque values give variable readings even under controlled conditions. I torque critical components and gladly use degree of rotation wherever I see it. I wish DOR was used more often, such as with the crankshaft balancer. I don't have a torque wrench that goes to 300Nm. So I went to 200Nm (the limit of my beam type), then I torqued with a 1 1/16" open end, pushing on the end-13 1/2" inches from center with a large, known mass (me). That's my take on it.

Except where MB says in the manual " add 90 degrees" .... I have never even heard of this....

I do know that a dirty sand filled hole being penetrated by a bent up bolt will pull down LESS than the engineers HOPED when they wrote down the torque numbers in the instructions....

And where gaskets are concerned that can sure make a mess...

This " DOR " has to START somewhere...... WHERE ?

This " DOR " has to START somewhere...... WHERE ?
Amen!!!

This " DOR " has to START somewhere...... WHERE ?

Hopefully from torque applied to joints carefully prepared such as the way you describe Greg. An initial torque with clean, lightly lubricated fasteners provides a good starting point because even though the variability of preload is high as a percentage of load, the variability of the final load after DOR tightening will be much lower. A combination of torque and then DOR tightening provides consistency of preload

I think it says something about those who drive/work on these cars that there is such a lengthy discussion about this torque issue.

I am not saying it is completely correct, but the only time I have ever seen any of the three mechanics in my family use a torque wrench at all was when tightening head bolts. Seems to me maybe you all are making mountains out of mole hills, but it does provide interesting reading.

Ok,,, so you are describing what the MB manual describes ?

MattDave sounded like it was a ' substitute' DOR for torque readings ...

So we still need to take the fasterners down in the number order which MB gives...

Do it incrementally.... just like all large important gasket jobs prescribe....

let it rest the amount after reaching the specified MB torque number....

Let it rest the ten minutes or whatever.... and do the ' turn an additional 90 degrees' .... perhaps twice ? ... whatever the manual says ...

So my impression is that these are used TOGETHER.... thus the question about which torque wrench... or which type....is still valid... Right ?

Habernero.... your relatives probably did not work on aluminum blocks ....or heads... Shop manuals like Subaru are careful to specify torque values for almost every bolt on the engine... and many on the car....You are probably young enough you have never had the job of trying to restore a bolt hole which had been stripped out.... never fun....

No offense but these old cars are not jet engines or F1 cars. Any torque wrench is good enough. Sears was selling a Craftsman wrench for $100 I bet you could get it on sale in the $70 range. If the manual says 30nm and your wrench is a little to high or low no big deal. You are not going to ruin a part on these cars buy having it tightened to 32 insted of 30.

No offense but these old cars are not jet engines or F1 cars. Any torque wrench is good enough. Sears was selling a Craftsman wrench for $100 I bet you could get it on sale in the $70 range. If the manual says 30nm and your wrench is a little to high or low no big deal. You are not going to ruin a part on these cars buy having it tightened to 32 insted of 30.

$30 will get you your first torque wrench. You will be more concerned with storing it so that you can find it next time you need it, it may be a while.

I bought my first torque wrench at advance auto parts for around $30. I used it to replace a head gasket on a Dodge Daytona Turbo. It worked just fine and I still use it on my car. If I was working on internal engine components on my MB, however, I would buy something of a little better quality to be safe. For everything else on my car, I think it's good enough.

Scott

"No offense but these old cars are not jet engines or F1 cars."

No offense Hatterasguy.....but our cars have almost twice the compression ratio of those F1 cars ....and don't get taken apart between every race... not even every decade.... if done properly...
Sounds like you are too young to have experienced some of the off the wall mechanical things some of us have.... and we swear we are not going to repeat them.... thus we start trying to learn what works and what does not...

Habernero.... your relatives probably did not work on aluminum blocks ....or heads... Shop manuals like Subaru are careful to specify torque values for almost every bolt on the engine... and many on the car....You are probably young enough you have never had the job of trying to restore a bolt hole which had been stripped out.... never fun....

Dad was out of the game before many aluminum engines were around, but my brothers both work on modern aluminum engines all the time. Maybe they are just lucky...

And by the way I have actually had to drill and retap a few holes I have buggered. Learned my lesson eventually.

Unless you're rebuilding the engine, there is really no need for a torque wrench in working on these cars. Just cinch things down tight and be happy with the money you've saved.

Merry Christmas,

Unless you're rebuilding the engine, there is really no need for a torque wrench in working on these cars. Just cinch things down tight and be happy with the money you've saved.

Merry Christmas,


Although I almost always agree with you, Larry, the wheel lugs and the brake caliper mounting bolts clearly require the use of a torque wrench. The risk of just "cinching things down tight" is not worth it for these items, IMHO.

I think it takes a bit of practice to know how tight different bolts should be, but overall I agree with Larry that most of the time you don't need a torque wrench if you've had some experience. I don't have a torque wrench either and I tighten bolts by feel according to their size.

The original post was looking for a torque wrench recommendation. I have a Craftsman click-type torque wrench that have served me well. Its a big one, 30 to 300ft/lbs. I got it to torque the balancer bolt on the truck which is 300ft/lbs. and the biggest thing I've ever torqued down. So far after many years of use the old Craftsman works quite well and has never let me down. RT

RT, I was about to say the same thing about the original post...
He asked for suggestions about them... not whether or not he should have one...
I believe in adding tools to anyone's collection that wants them...
Now, if you negative guys had his full list of tools that he owns...and wanted to recommend something else as NEXT purchase... great.... but you don't... and I think anyone that wants tools ought to be encouraged to round out their collection...
I don't believe in always waiting until you have a problem AT HAND... and then going out to get the tools you need to fix it... sometimes THAT problem AT HAND is your only transportation....
If you have FACTUAL negative information .... like which don't work as well as others .... great....
But just negative attitude does not look good considering the question....

From the information I've been given and considering I'm what you would call frugal, I think my initial investment will be a 1/2in beam type wrench and a good 3/8in. I wasn't considering the beam type because I wrongly assumed their accuracy would not be on the level of the more expensive "click" type. When I have the extra funds I will invest in the "click" type for situations when the other is difficult to use.

Thanks for all the information.

To develop a feel for torquing fasteners you are feeling for a rapid increase in resistance. As you are tightening, it will take a fairly consistent torque to turn the fastener. You are feeling the resistance due to friction. As you start to stretch the fastener you will feel it increase in resistance rapidly. At this point you tighten a little more and you will be at the specification for that fastener. It is subjective and takes practice to develop the feel. Fasteners that tighten to much over 75lbs of torque are very difficult for me to judge, I alway use a torque wrench for critical values in this range.

Tightening small fasteners is tricky 'cause they are easy to break. Use a short handle and grip it near the center of rotation so that you do not have the mechanical advantage of a long lever.

If you ever feel a fastener spring back from the right torque it is either bottomed in the hole or the threads are fouled. That fastener will not do its job and you have a problem that must be fixed before you can proceed.

Sometimes a click wrench does not click at the specified torque. Sometimes you are feeling for the spring tension to break. You must move the wrench back and forth at that torque to feel it. You are going by feel and not by sound.

Some torque wrenches have a pivot in the handle. You must balance that pivot and pull with the handle centered on the pivot to get the correct torque.

I have been wrenching for most of my life and I think I have a pretty good feel developed for how "tight" is good enough. I don't care for beam-type torque wrenches as it is difficult, for me anyway, to read the scale accurately while pulling hard and leaning over and engine compartment torquing something like headbolts. Another area where "feel" doesn't work is the new "stretch" or torque-to-yield fasteners. I just did the headgasket on my 300D and there is no real change in resistance when turning in the two additional 90* turns after the initial preload torquing steps. You can't tell by feel because the bolts are stretching and they are doing so much more than a standard "old style" bolt. Not that I would recommend just tightening headbolts by feel, I wouldn't. I would however pay careful attention to the type of fastener you are working with, what it secures and how it should be tightened. Torque specs are there for a reason. I use a torque wrench on anything that is internal engine, reciprocating, wheel or suspension related. Once you own one you will use it more than you think. RT

It's amazing that I've maintained about 800,000 miles worth of 123's without ever using a torque wrench on brake calipers or lug bolts. In that time I have never had a wheel come off, or a brake rotor warped. I also have never had a brake caliper problem (BTW, you should use blue loctite on the brake calipers.)

To tighten lug bolts, snug them in a five pointed star pattern, then put your weight on the lug wrench in a five star pattern to tighten them evenly. Like I say, this method has worked for 800,000 miles worth of 123 maintenance and untold hundreds of thousands of miles on other cars.

If you're such a wuss that you can't get a brake caliper bolt tight enough so that it won't fall out without using a torque wrench, then you should NOT be doing brake work.

I was merely trying to point out to the original poster that he could save his money and put it toward something more useful, but as has happened too often here on mshop, I have been blasted for offering advice. This blasting more often than not comes from the same person.

Merry Christmas,

Merry Christmas Larry.... you are FULL OF IT !!!

Concering the brake work... the idea is to NOT TIGHTEN TOO MUCH... not that help is needed to secure it...
Concerning putting your weight on the lug wrench.... so it makes no difference that some guys weigh 130 lbs.... and others 290 ?
And concerning ' more useful tools' ... you failed to state your recommendation... which of course was due to you not knowing what he already owns... as I mentioned above....

Duh! Well common sense is more what it takes, but I guess some people just don't know how to use a torque wrench. If you tighten too much, two things can happen, it either breaks off or you might not get it off when you go to take it off. To loose and and something is going to give or break. When I purchased my SDL, I noticed about 3 months later that someone had overtighted my lug bolts. One was twisted off, took some time to get it off, but it did have to be drilled out. I grew up in a shop, fixing flats, I never used a torque wrench on lug bolts. I'd tighten the bolts snug with a little extra snug, with the air ranch, that was that. I never had anyone complain about my tightening of their lug bolts.

However, some people that don't understand the physics of tightening too much may need a torque wrench, of course thats if they know how to use it. :bulb:

In the famous 'Compleat Idiot's Guide to VW Maintainence' the author has a fairly detailed description of how to judge torque by feel, and properly torque a fastener through consistently applied force instead of jerking or slamming motions. I'd say its required reading for people wrenching their own cars.

That said, I own a torque wrench, a 30$ 1/2" click-type I bought at Harbor Freight. Is it super-accurate? No. Is it close? Yes. I use it when doing wheel, brake and suspension stuff, and it gives me a good baseline.

I wouldn't spend 300$ on a torque wrench unless I was rebuilding ultra-precision engines (which these aren't, which is why they last so long (wide tolerances)), or was using my torque wrench every day.

30$ was cheap insurance for me on critical applications.

peace,
sam

" If you tighten too much, two things can happen, it either breaks off or you might not get it off when you go to take it off. "

A third thing can happen .... which is often more problems than those two.. that is stripping the threads out of the hole... important holes... head bolts, brake items.... very hard to do a correct job fixing.... much better to prep the holes, the bolts, and use a torque wrench.... chances of catastrophic failure are taken almost to zero....

However, some people that don't understand the physics of tightening too much may need a torque ranch, of course thats if they know how to use it. :bulb:

Tom, as an engineer, physicist and 30 year wrencher, I hope I understand torque. I design automated machinery for a living, creating solid models of unique equiptment from scratch. However, I can't draw to save my life, I'm a Klutz, have trouble with social graces and I have trouble with overtightening bolts. It's just one of those things. I'm pretty much where Larry is on tightening philosophy, but I've found myself using the torque wrench a little more. Just recently I torqued the brake calipers and steering arms, after cleaning the holes and applying blue loctite. I'm not really a wuss, but I'm tired of breaking stuff because I overtightened it or having a hell of a time loosening something I previously tightened. Some people have trouble with the "feel", and I'm one of them.

So long and have a Merry Christmas.

Pete and Larry, I don't disagree with either of you. Both make good points on the uses and non uses on torque wrench use. Like i said, I didn't use that growing up, but now after witnessing my lug bolts on my car and seeing how much it cost for taking them off. It's probably better to use a torque wrench. I see this at all the major tire shops now. They use a torque wrench to finish off the job. Heck they don't want to spend the extra money in putting on new lug bolts, better yet getting them off after they've twisted one off. Try taking them off a SDL, the way the wheels are built, especially if one is broke off up inside. Those lug bolts on the 126 are easy to bend.

"No offense but these old cars are not jet engines or F1 cars."

No offense Hatterasguy.....but our cars have almost twice the compression ratio of those F1 cars ....and don't get taken apart between every race... not even every decade.... if done properly...
Sounds like you are too young to have experienced some of the off the wall mechanical things some of us have.... and we swear we are not going to repeat them.... thus we start trying to learn what works and what does not...

Lets see F1 engines displace about 3 liters run to 18k+ rpm and put out around 700hp(I think) Yeah next time I am running my 603 at 220mph I will just hope a piston doesn't fly out of the hood because some German was a little to tight on the rod cap bolts. :rolleyes:

I have used a torque wrench on my IP seals and injectors and other sensitive parts. Other than that tight is good enough I know how to tighten a bolt enough not to have problems. Sorry my MB is not a rocket ship if my shock bolts are 18nm insted of 20 I know my car will just explode. :D

Signing off and getting back to the real world of working on old rusty MB's.

However, some people that don't understand the physics of tightening too much may need a torque ranch, of course thats if they know how to use it. :bulb:

Hey, not so fast on the edit there TOM. This torque ranch you speak of, is this some place all you guys in Texas go to learn about tightening fasteners? :laugh:

You are correct Pete...
As a matter of fact Randy is giving a Torqueing Demo this weekend...
but his place is a Torque Lot.... 100 feet by 150 feet.... and more than 5 Mercedes...
Later we will have one here on my Torqueing Farm... 30 acres and more than 5 Mercedes...
I do not know what the qualifications are for a Torqueing Ranch...must be a pretty big spread.... However , I do know that it qualifies you to tuck your pants legs inside your boot tops.....

Hey, not so fast on the edit there TOM. This torque ranch you speak of, is this some place all you guys in Texas go to learn about tightening fasteners? :laugh:
Okay Pete, I got it. :D , but at least I caught my error. :D

Only in Texas do they make them bigger and better :cowboy:

Well I slept on it before I made this decision and 7,950 posts is where it stops.

This person has tormented me for the last time on mercedesshop. This person would have something sarcastic to say if I were to start quoting from the phone book and I just don't need it. This decision is NOT based on this one single thread. This person has been blasting my posts on a regular basis for at least two years.

I hope everyone continues to enjoy their MB cars and I'm sure you'll get lots of help here at mercedesshop, but the last of it has come from me unless you have something specific in which case you can private mail me. The next time I need help, I'll just read the manuals a little more carefully or search the archives here. They have accumulated enough information to fix almost anything MB related.

Merry Christmas,

Larry, i'm confused, why would you not share your knowledge with all? I know that people sometimes disagree on things, but then that's the way it should be. It gives people different choices and alternatives to think about. You should keep on typing no matter what or who doesn't agree with you. You must be doing something right to have that kind of reaction. I don't know if there are any underlying cercumstances, but I wouldn't quit for no one....plus you really should go for 8,000 post, well make it 10,000.

I'm relatively New on here, but I do read your post and I think your post are invaluable. Hope your Reconsider. :)

Larry, I do hope you come back here at some time. I have benefitted a great deal from your insight here, especially when I was trying to make decisions about rebuilding my engine. Also, your post about the runaway issue you experienced with your daughter's car was the most selfless statement ever made here. The amount of frustration you have potentially saved others is immense. If I had not read that post, I could have easily done that to my rebuilt engine, and that would have been enough for me to give up my hobby forever. Instead, I will soon be able topost some pictures of what happened when I stopped by rebuild job in the middle and forgot to check 1 screw, and be able to recover from that without catastrophe. Before I ramble anymore, I want to say that it has been a pleasure to read your comments over the last 2 years. When I look at the postings, I look at the titles and also who has responded. When I see your name, I usually read it. That's because you have earned my respect with your words. Thank you, Larry. :)

I haven't read this entire post, and probably won't, but I want to make a comment about the use of torque wrenches. I would venture a guess that 95% of the people who own them have no idea how to PROPERLY use them or maintain them. Thus, who cares if you actually use one!!!! If you aren't, or don't know how to use one, then you might as well not use one at all. I would guess that most people store their wrenches set to some value other than the lowest setting, for an adjustable type wrench. This is a no-no since you are keeping a constant tension on the internal spring which can cause the wrench to become non-linear over time. I would also guess that most people give that wrench one more good tug once the wrench has "broken". What purpose does that serve? The wrench is supposed to "break" at a set point...why push that wrench past the break point. And one last comment...I would venture a guess that 99.99% of home mechanics do not get their torque wrenches calibrated periodically. Without doing this, how do they know that the wrench is breaking at the true set point? If you are making critical measurements, then you should get your wrench checked periodically.

Since 99.99% of those out there who own torque wrenches don't maintain them properly, they might as well put a big ol' breaker bar on the end of their wrench and give it a good tug...it is just about as precise.

Mike

Interesting logic. This is like saying that 95% of people who wear wrist watches do not properly maintain them. 99.99% of wristwatches are not 100% accurate, therefore we should tell time by observing the position of the sun.

The Mercedes service manual makes countless references to torque values. One can argue that an experienced mechanic can torque fasteners to specification by feel. If that is the case, I don't know how said mechanic developed such an accurate feel unless it was through the repeated use of a calibrated wrench. The average DIY'er is doing good if he can recognize the size of a fastener, let alone torque one correctly by feel. I will take a somewhat inaccurate torque wrench over a breaker bar any day.

We are close to blundering into a discussion of precision and accuracy. I will say that even an uncalibrated torque wrench can help someone be consistent and there is some value in that.

My previous post on tightening a fastener without a torque wrench was partially inspired because one needs to be aware that blind faith in one technique over all others can be a bad approach. When you tighten a fastener you need to be aware of what you are trying to accomplish and evaluate all sensory inputs and not just pull like hell and try to quit when the wrench says to. A large part of working successfully depends on really looking at what you are doing and evaluating as you go.

I have seen mechanics successfully use an air wrench for a torque wrench. Low setting, go through the pattern. Medium setting, go through the pattern. Torque wrench to finish, if needed. This technique is not recommended and could cause you problems if you are observed doing this.

When you torque something you should be thinking about levers, springs, strain, stress, circles, spirals and Fibonacci numbers. :)

"I will say that even an uncalibrated torque wrench can help someone be consistent and there is some value in that. "---TwitchKitty

Amen !

Particularly when dealing with Cast Iron items repeatedly subject to thermal stress cycles...

The local tech kollege has a calibrator for torque wenches. I take mine down every 6 months or so just to check on it. Especially if I have a big project. I have seen the best of mechanics who swear by a torque stick. After they have done it, I take a torque wench and test them all. What do I find? Out of 5 bolts, 3 have different torque values.

I propose a test. To those who say they can do it by feel, can you prove it? Ie, have say 100 different bolts and torque them to their specs and have it verified by a torque wrench for accuracy and consistency. If that doesn't settle the arguement once and for all, I don't know what will.

Local tech kollege, huh? While you are down there, you might want to swing by the English Department...

Local tech kollege, huh? While you are down there, you might want to swing by the English Department...

Hey, huked on fonix wurks for me.

The local tech kollege has a calibrator for torque wenches. I take mine down every 6 months or so just to check on it. Especially if I have a big project. I have seen the best of mechanics who swear by a torque stick. After they have done it, I take a torque wench and test them all. What do I find? Out of 5 bolts, 3 have different torque values.

I propose a test. To those who say they can do it by feel, can you prove it? Ie, have say 100 different bolts and torque them to their specs and have it verified by a torque wrench for accuracy and consistency. If that doesn't settle the arguement once and for all, I don't know what will.
Does anyone here really give a crap one way or the other??? :argue:

I don't! :sleeping:

Aklim, just curious as to what type of torque wrench you have and what you find when you get the calibration checked. How far off does it get in six months?

I do. I'm curious because I have heard of techs saying they can do it by feel but no one has proven it to me that they are consistant and accurate yet. For that matter, they haven't proven the opposite yet so yes, I am interested to know if it is possible or not.

Aklim, just curious as to what type of torque wrench you have and what you find when you get the calibration checked. How far off does it get in six months?

I have a Sears craftsman one. Not the beam style, click style. I am a DIYer so I don't use it as much as a tech. So far, it is on. I relieve the pressure when I am done religiously. I hold it by the handle and put the square end into the calibration device. I turn it till it clicks at the setting I have it set for and note the reading on the device. Like I said, so far, it is on the money. The device gets checked out every few months so I can assume it is somewhat accurate.

I do. I'm curious because I have heard of techs saying they can do it by feel but no one has proven it to me that they are consistant and accurate yet. For that matter, they haven't proven the opposite yet so yes, I am interested to know if it is possible or not.
Informed people want to know. :bowrofl:

I have a Sears craftsman one. Not the beam style, click style. I am a DIYer so I don't use it as much as a tech. So far, it is on. I relieve the pressure when I am done religiously. I hold it by the handle and put the square end into the calibration device. I turn it till it clicks at the setting I have it set for and note the reading on the device. Like I said, so far, it is on the money. The device gets checked out every few months so I can assume it is somewhat accurate.
That's what I suspected. I don't buy all these claims that torque wrenches are wildly inaccurate. I was quite involved with tool calibration in a previous life, and I seldom saw a click or dial tool the was more than 2-3% off when they came through cal.

I propose a test. To those who say they can do it by feel, can you prove it? Ie, have say 100 different bolts and torque them to their specs and have it verified by a torque wrench for accuracy and consistency. If that doesn't settle the arguement once and for all, I don't know what will.

Tightening by feel would probably not produce as consistent results as a torque wrench would, but I firmly believe that unless you're working on something critical like a head, you don't need perfect consistency, just moderate consistency easily attainable by hand. The idea is to tighten a bolt tight enough so it's not gonna get loose or cause seepage while not so tight that you're gonna strip the thread, break it or warp something. I've never had any problem with this approach. I'd rather tighten my bolts to what feels right from experience, rather than to some number which could be misprinted or by a torque wrench which could be miscalibrated.

The local tech kollege has a calibrator for torque wenches. I take mine down every 6 months or so just to check on it. Especially if I have a big project. I have seen the best of mechanics who swear by a torque stick. After they have done it, I take a torque wench and test them all. What do I find? Out of 5 bolts, 3 have different torque values.

I propose a test. To those who say they can do it by feel, can you prove it? Ie, have say 100 different bolts and torque them to their specs and have it verified by a torque wrench for accuracy and consistency. If that doesn't settle the arguement once and for all, I don't know what will.
There is no argument here to settle.

You don't have to settle an argument with a man who packs his own parachute, if you hear him say he's right, he proved he's right.

I hate torque sticks and don't use them. A torque stick on an impact is about useless. I see that several shops require them (not mine), mainly for wheel tightening. The main problem is they are very dependent on your guns output, it's speed setting and how long you hammer away each time you use it. Tightening in a criss-cross pattern is more important. I've seen mechanics that hammer away a bolt at a time in a circle, sometimes lingering on a bolt for 10 or more seconds after it's tight. :eek:
It's more important to criss-cross when tightening wheels (just as with anything else) in a couple passes and have a feel for what gun your using if you're going to use one instead of using a torque stick and just hammering away in a circle. I use torque wrenches on crital items (such as engine internals, heads, etc.) and would question anybody using a torque stick on these items.

I will never look at a torque wrench the same way again. :D

Next.........................

Interesting logic. This is like saying that 95% of people who wear wrist watches do not properly maintain them. 99.99% of wristwatches are not 100% accurate, therefore we should tell time by observing the position of the sun.

The Mercedes service manual makes countless references to torque values. One can argue that an experienced mechanic can torque fasteners to specification by feel. If that is the case, I don't know how said mechanic developed such an accurate feel unless it was through the repeated use of a calibrated wrench. The average DIY'er is doing good if he can recognize the size of a fastener, let alone torque one correctly by feel. I will take a somewhat inaccurate torque wrench over a breaker bar any day.

Everything has a certain degree of uncertainty to it. It is how well you can realize this uncertainty and account for it that matters. If you don't take into account any of the uncertainty, you might as well fly blind, or in this case not use a torque wrench at all. I manage a calibration lab for a living and deal with issues like this on a daily basis. It is amazing how little people actually know about the equipment they use day in and day out. I am not trying to say that we shouldn't use precise methods when called for, what I am trying to get across is that if you are going to use a torque wrench, you should maintain it and use it properly.

Mike

All the shop manuals I have seen list a RANGE of torque values for any particular bolt....
perhaps they are taking into account a certain lack of certainty with regards to torque wrenches or their ' drivers'....

Someone already mentioned one of the most important abilities of a torque wrench... and it has NOTHING to do with its absolute numerical accuracy...
That is the ability to ' take down' something like a head ... using the proper number sequence for the bolts... given in the Shop manual... IN small EVEN Increments... this is particularly important on Cast Iron things... as they are tend to be more fragile than some other metal castings....

I manage a calibration lab for a living and deal with issues like this on a daily basis.
Mike

Mike,
I would be interested knowing what you typically see when you calibrate a torque wrench. What is the typical error (%) using a mid-range torque value, at one and two standard deviations from the mean? Thanks.

Early on in this thread I posted about a faa reg reguarding using the click typ tourque wrench I was wrong the faa is not in any way dissalowing the use of the non baR type wrench. Just to set the record straight.
Dave S

Just curious... Has anyone used the craftsman torque meters? Looks like they are just a strain gauge hooked up to an electronics box to give the angular force applied.

http://www.webbikeworld.com/r2/torque/torque.htm

Take a look at the link, I saw it the other day and it still looks clumsy. I will stick with my CLICK torque wrench for now.

As the guy review the Electronic Torque Meter, it is not so handy tool.

;)

http://www.webbikeworld.com/r2/torque/torque.htm

Take a look at the link, I saw it the other day and it still looks clumsy. I will stick with my CLICK torque wrench for now.

As the guy review the Electronic Torque Meter, it is not so handy tool.

;)

If it sent a wireless signal it's be neat, but having to have a cable makes it clumsy (as you said).

Harbor Freight has their click torque wrenches on sale for $10... half price....

http://www.harborfreight.com/cpi/ctaf/category.taf?f=clearancesale&categoryid=3&pricetype=C&categoryname=HAND%20TOOLS

If it sent a wireless signal it's be neat, but having to have a cable makes it clumsy (as you said).


So, I bought one of the craftsman electronic torque gauges off of Ebay for about $50. The cable is annoying at times but less so than working on a chevy at any given time. My favorite feature is the audible beeping that gets closer and closer to a tone when you reach the correct torque. I think I'm gonna keep this one and my 1/2" clicker too.

Harbor Freight has their click torque wrenches on sale for $10... half price....

http://www.harborfreight.com/cpi/ctaf/category.taf?f=clearancesale&categoryid=3&pricetype=C&categoryname=HAND%20TOOLS
I was very disappointed in the click torque wrench that was purchased at Harbor Freight. The action seems to hang up sometimes and causes me to question the accuracy. If $$ are tight,(why I bought it) it will get you by, but I found a reasonably priced one at Northern Tool that performs a little better.

I did not buy or try it.... just saw it on the website.... your report of its feel does not surprise me... some things are safe to buy cheap on sale...and others are ' IFFY'... we will put that one into that category...
I still have my 30 year old spring bar types... so you know I am cheap...
We ought to fix a really simple but accurate device to test torque wrenches and post a picture .... all it would need is a nut on the end of a tube to fit any socket one has for their Twrench ( so one would need two in order to check both lb feet and inch lb ranges )... a way to mount it horizontally and a way to hang weights at various distances from that nut...
While crude in look... this same method can be used with Great accuracy when balancing the weight of things like pistons... I have seen 10 ft EM tubing used for this sort of thing...very accurate when applied correctly.

Something very similar to the sliding weights on a cantilever scale sounds like what you have in mind.

Yes, there are some things you can get by with at cheaper Harbor Freight, but many items need to be checked out very thoroughly. If someone is very familiar with the quality details to look for, they can chance on to a good buy. Stay away from ary of their ratchets. Terrible quality.

Northern Tools has better quality and you will pay a little more. A little more bang for the buck. They also sell S&K brand on their website which is professional quality.

Their Titan brand (even though it is made in Taiwan) is the best of both worlds. I would recommend Titan for torque wrenches and ratchets, which are excellent quality for the money.

"Stay away from ary of their ratchets. Terrible quality."
Unfortunatly this has applied to my experience with Sears Craftsman ratchets... for many years.... which really pains me because I love the rest of their hand tools... ( but in general avoid Sears items which have motors attached ).
Yesterday I got one of the 1 inch ( ONE INCH !!!! ) drive impact wrenches...from Harbor Freight for $124 ...half what they claim is regular price..... just could not resist trying it.. since I am about to split my old 340 Farmall Tractor... I can barely pick the thing up.. but it says 1400 lbs of torque if you give it enough air...if they cut any corners on manufacturing or designing it it was on the inside.. because it is beautiful on the outside.

Ahh, there is nothing like banging away with an inch impact. Takes a ton (I mean a ton) of air to keep it fed, though. Big compressor, big feed hose. I don't know about the newer styles, but Dad's older Chicago Pneumatic requires a line oiler (unlike smaller impacts where you can get away with dribbling a drop or two in the inlet every once in a while).

I just helped Dad put a new rear case (and newer gears and new bearings) in one of his Farmall M's this last winter. The summer before it broke a tooth off a gear which then proceeded to go between the gear and the case. I guess it made a heck of a bang when it cracked.

Checking a torque wrench can be as simple as applying vertical force on the wrench while standing on an accurate bathroom scale. Checking both ways accounts for hysteresis. You don't need a fancy torque meter. If you want accuracy, check your bathroom scale against the one at your doctor's office. I know my bathroom scale is shot, because the weight it reads keeps going up. :rolleyes:

I have an inline oiler and will move it to this tool...
I am way underpowered on air at this time....( for this operation )
I am thinking I will need to mount my 60 gallon upright on a trailer and run it off the pto of the 5600 Ford diesel ..... which also lets me do it anywhere on the farm that has level ground ...

Hum... that makes me wonder if I need to get a bigger oiler so as to not have a bottleneck in airsupply.... I doubt my old regular one has 3/8ths holes....

Not sure what size Dad's oiler is. Older than the hills, I think, but still seems to work. He still uses one of his 1/2" CP impacts that he bought when he opened his shop in 62.